Answer: The unwanted earthy impurities mixed with the ore mineral.
- A The unwanted earthy impurities mixed with the ore mineral
- B The valuable metal extracted from the mineral itself
- C The reducing agent added during the smelting stage
- D The slag formed later during the smelting process
Correct answer: A. The unwanted earthy impurities mixed with the ore mineral
Explanation: Gangue is the unwanted non-metallic material (clay, sand, rock) mixed with the ore mineral.
An Ellingham diagram plots ΔG° of oxide formation against temperature for different metals; whichever line is LOWER (more negative ΔG°) at a given temperature reduces the oxide of any metal whose line sits above it - the basis of carbon reduction (Fe, Zn) vs electrolytic reduction (Al, Mg, Na) decisions.
Concept context
The science of extracting metals from ores and refining them for use. Covers concentration methods, reduction techniques, refining processes, and the thermodynamic principles that govern metal extraction.